Power supply device of video display apparatus and method thereof

ABSTRACT

A power supply device of a video display apparatus and a method thereof is capable of improving operation reliability of a video display apparatus, preventing erratic operation of the video display apparatus caused by higher harmonics and preventing erratic operation of other apparatus caused by unnecessary transmitted radiative wave. The power supply device can include a rectifying section for converting AC power into DC power, a harmonic suppressor for cutting off higher harmonics included in the DC power and a smoothing circuit for smoothing the higher harmonics cut-off DC power. A standby power supplier is for supplying the smoothed DC power to the video display apparatus as standby power, a main power supplier is for supplying the smoothed DC power to the video display apparatus as main power and a control unit is for controlling an operation of the harmonic suppressor.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a video display apparatus, andin particular to a power supply device of a video display apparatus anda method thereof.

[0003] 2. Background of the Related Art

[0004] In general, it is very important to supply stable power to avideo display apparatus. Further, it is required to restrain generationof unnecessary radiative wave (in particular, higher harmonics) causedby noise or internal/external causes and prevent higher harmonics frombeing transmitted to other parts or other apparatus through a power lineor an additional common line to guarantee operation reliability of thevideo display device.

[0005] For example, because higher harmonics are related to EMI(electromagnetic interference), when higher harmonics reach a videodisplay apparatus, they can cause fatal damage to the operation of thevideo display apparatus. In particular, when higher harmonics generatedin the power supply device ate supplied to the video display apparatus,they can have a bad influence upon operation reliability or stability ofthe video display apparatus. In addition, because higher harmonics canbe easily transmitted to other apparatus through a power line connectedwith the video display apparatus, higher harmonics in the power supplydevice have to be prevented.

[0006]FIG. 1 is a block diagram illustrating a power supply device of avideo display apparatus in accordance with the related art. As shown inFIG. 1, the power supply device of the video display apparatus includesan AC power input block 101, a filtering unit 102 for removing EMI(electromagnetic interference) from AC power received through the ACpower input block 101 and a rectifying section 103 for converting ACpower outputted through the filtering unit 102 into DC power. A standbysmoothing circuit 104 and a standby power supplier 105 supply DC poweroutputted from the rectifying section 103 to the video display apparatusas standby power. A harmonic suppressor 106 is for cutting off higherharmonics included in DC power (e.g., DC power including ripple element)outputted from the rectifying section 103. A main power smoothingcircuit 107 and a main power supplier 108 provide DC power outputtedfrom the harmonic suppressor 106 to the video display device as mainpower.

[0007] The operation of the power supply device of the video displayapparatus in accordance with the related art will be described withreference to FIG. 2. FIG. 2 is a graph showing ripple waveforms (i.e.,voltage waveform 201, current waveform 202) of a voltage and currentinputted to the standby power supplier 105 installed at the power supplydevice of the video display apparatus in accordance with the relatedart.

[0008] First, the filtering unit 102 removes EMI by removing noiseelement included in the AC power applied from the AC input block 101 andoutputs the noise-removed AC power to the rectifying section 103. Therectifying section 103 converts the noise-removed AC power into DC powerand respectively supplies the converted DC power to the standby powersmoothing circuit 104 and the harmonic suppressor 106. The DC poweroutputted through the rectifying section 103 includes ripple element.

[0009] The standby power smoothing circuit 104 smoothes the DC powerincluding the ripple element and outputs the smoothed DC power to thestandby power supplier 105, and the standby power supplier 105stabilizes the smoothed DC power to supply the stabilized DC power tothe video display apparatus as standby power. The standby power supplier105 supplies the DC power including the higher harmonics to the videodisplay apparatus.

[0010] In the meantime, the harmonic suppressor 106 cuts off the higherharmonics of the DC power including the ripple element outputted fromthe rectifying section 103 and outputs the higher harmonics-cut off DCpower to the main power smoothing circuit 107. The main power smoothingcircuit 107 smoothes the higher harmonics-cut off DC power and suppliesthe smoothed DC power to the main power supplier 108. Herein, the mainpower supplier 108 stabilizes the smoothed DC power and supplies thestabilized DC power as main power of the video display apparatus.

[0011] When the power supply device of the related art video displayapparatus is in a standby power supply mode, since there is no means forcutting off the higher harmonics applied to the standby power supplier105, the higher harmonics generated by a rush current is supplied to thestandby power supplier 105. In more detail, only higher harmonicsincluded in the power supplied to the main power supplier 108 areremoved. Higher harmonics included in the power supplied to the standbypower supplier 105 are not removed by the current waveform (e.g., rushcurrent) 202 as depicted in FIG. 2. Accordingly, the video displayapparatus may perform erratic operation because the DC power includingthe higher harmonics generated by the rush current is supplied to thestandby power supplier 105.

[0012] In addition, the higher harmonics applied to the standby powersupplier 105 may be transmitted to other apparatus through the standbypower supplier 105 and a power line (not shown) and cause erraticoperation of the other apparatus. For example, since the higherharmonics of the standby power has a bad influence upon the main powersupplier 108, the video display apparatus may perform erratic operation.

[0013] As described above, the related art power supply device of thevideo display apparatus has various disadvantages. The related art powersupply may cause erratic operations by applying the higher harmonics tothe standby power supplier. In addition, in the related art power supplydevice of the video display apparatus, because the higher harmonics maybe transmitted to other apparatus connected to the AC power line throughthe AC power input block, other apparatus may perform erratic operation.

[0014] The above references are incorporated by reference herein whereappropriate for appropriate teachings of additional or alternativedetails, features and/or technical background.

SUMMARY OF THE INVENTION

[0015] An object of the invention is to solve at least the aboveproblems and/or disadvantages and to provide at least the advantagesdescribed hereinafter.

[0016] Another object of the present invention to provide a power supplydevice of a video display apparatus and a method thereof capable ofimproving operation reliability of a video display apparatus bysupplying higher harmonics-cut off DC power to the video displayapparatus as standby power and main power.

[0017] Another object of the present invention to provide a power supplydevice of a video display apparatus and a method thereof capable ofreducing or preventing erratic operation of a video display apparatuscaused by higher harmonics by supplying higher harmonics-cut off DCpower to the video display apparatus as standby power and main power.

[0018] Another object of the present invention to provide a power supplydevice of a video display apparatus and a method thereof capable ofreducing or preventing erratic operation of other apparatus caused byunnecessary radiative wave transmitted thereto by supplying higherharmonics-cut off DC power to the video display apparatus as standbypower and main power.

[0019] In order to achieve at least the above-described objects in awhole or in part, a power supply device of a video display apparatus inaccordance with the present invention includes a rectifying section forconverting AC power into DC power; a harmonic suppressor for cutting offhigher harmonics included in the DC power; a smoothing circuit forsmoothing the higher harmonics cut-off DC power; a standby powersupplier for supplying the smoothed DC power to the video displayapparatus as standby power; a main power supplier for supplying thesmoothed DC power to the video display apparatus as main power; and acontrol unit for controlling an operation of the harmonic suppressor.

[0020] To further achieve at least the above-described objects in wholeor in part, a power supply device of a video display apparatus inaccordance with the present invention includes a filtering unitconfigured to remove electromagnetic interference by filtering AC power,a rectifying section configured to convert the filtered AC power into DCpower, a coil unit configured to cut off higher harmonics included inthe DC power converted by the rectifying section and applies the higherharmonics cut-off DC power, a switching unit configured to apply the DCpower converted by the rectifying section to the smoothing circuitthrough the coil unit by being turned off in a standby power supply modefor supplying the standby power to the video display apparatus, whereinthe switching unit provides the DC power converted by the rectifyingsection to the smoothing circuit by coupling the coil unit to areference voltage or through the coil unit by being selectively enabledin a main power supply mode for supplying the main power to the videodisplay apparatus, an operation unit configured to control an operationof the switching unit, a smoothing circuit configured to smooth thehigher harmonics cut-off DC power applied from the coil unit, a standbypower supplier coupled to the smoothing circuit and configured to supplythe smoothed DC power to the video display device as the standby power,a main power supplier coupled to the smoothing circuit and configured tosupply the smoothed DC power to the video display device as the mainpower; and a control unit configured to control the operation unit toturn off the switching unit in the standby power supply mode andselectively enable the switching unit in the main power supply mode,wherein higher harmonics generated by a rush current included in the DCpower converted by the rectifying section is cut off by coupling thecoil unit to the reference voltage.

[0021] To further achieve at least the above-described objects in awhole or in part, a power supply method of a video display apparatus inaccordance with the present invention includes converting AC power intoDC power, removing higher harmonics included in the DC power in each ofa first power supply mode for supplying power to a video displayapparatus and a second power supply mode for supplying power to thevideo display apparatus, smoothing the higher harmonics removed DCpower, supplying the smoothed DC power to the video display apparatus asstandby power, and supplying the smoothed DC power to the video displayapparatus as main power.

[0022] Additional advantages, objects, and features of the inventionwill be set forth in part in the description which follows and in partwill become apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objects and advantages of the invention may be realizedand attained as particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention will be described in detail with reference to thefollowing drawings in which like reference numerals refer to likeelements wherein:

[0024]FIG. 1 is a block diagram illustrating a power supply device of avideo display apparatus in accordance with the related art;

[0025]FIG. 2 is a graph showing ripple waveforms of a voltage andcurrent inputted to a standby power supplier installed at the powersupply device of the video display apparatus in accordance with therelated art;

[0026]FIG. 3 is a circuit diagram showing a power supply device of avideo display apparatus in accordance with a preferred embodiment of thepresent invention; and

[0027]FIG. 4 is a graph showing ripple waveforms of a voltage andcurrent outputted through a harmonic suppressor in accordance with apreferred embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0028] Preferred embodiments of a power supply device of a video displayapparatus and a method thereof in accordance with the present inventionare capable of improving operation reliability of a video displayapparatus, reducing or preventing erratic operation of the video displayapparatus caused by higher harmonics and reducing or preventing erraticoperation of other apparatus caused by transmitted unnecessary radiativewave. Preferred embodiments of a power supply device of a video displayapparatus and methods thereof can convert AC power into DC power and cutoff or reduce higher harmonics included in the DC power in a standbypower supply mode for supplying standby power to a video displayapparatus and a main power supply mode for supplying main power to thevideo display apparatus.

[0029]FIG. 3 is a circuit diagram showing a preferred embodiment ofpower supply device of a video display apparatus in accordance with thepresent invention. As shown in FIG. 3, the power supply device of thevideo display apparatus in accordance with a preferred embodiment of thepresent invention can include an AC power input block 301, a filteringunit 302 for removing EMI (electromagnetic interference) by filteringthe AC power received through the AC power input block 301 and arectifying section 303 for converting the AC power filtered in thefiltering unit 302 into DC power. A harmonic suppressor (or a powerfactor correction circuit) 304 is for cutting off or reducing higherharmonics included in the DC power converted by the rectifying section303. A control unit (e.g., a microcomputer) 305 is preferably forcontrolling the harmonic suppressor 304 according to a standby powersupply mode or a main power supply mode. A smoothing circuit 306 cansmooth the higher harmonics-cut off DC power, a standby power supplier307 can supply the DC power smoothed by the smoothing circuit 306 to thevideo display apparatus as standby power and a main power supplier 308can supply the DC power smoothed by the smoothing circuit 306 to thevideo display apparatus as main power.

[0030] The harmonic suppressor 304 can include a coil unit 304-1preferably serial-coupled between the rectifying section 303 and thesmoothing circuit 306 to cut off or reduce the higher harmonics includedin the DC power converted by the rectifying section 303 and apply thehigher harmonics-cut off DC power to the smoothing circuit 306. Aswitching unit 304-2 can supply the DC power to the smoothing circuit306 by grounding the coil unit 304-1 or through the coil unit 304-1, anda switching operation unit 304-3 can control (e.g., switch) theswitching unit 304-2 according to a control signal of the control unit305.

[0031]FIG. 4 is a graph showing ripple waveforms (e.g., voltage waveform401, current waveform 402) of a voltage and current outputted from theharmonic suppressor 304. As shown in FIG. 4, the higher harmonicsgenerated due to a rush current are removed or reduced by cutting offthe rush current (e.g., 202 in FIG. 2) preferably by switching thecurrent signal (e.g., current waveform 402) within an envelope level ofthe voltage waveform 401 of the DC power outputted from the rectifyingsection 303.

[0032] For example, the coil unit 304-1 of the harmonic suppressor 304can cut off the inflow of the rush current, and the rush current cut-offcurrent waveform 402 having a gentle curve such as a sine wave flowsinto the smoothing circuit 306. The rush current 202 inputted to thecoil unit 304-1 of the harmonic suppressor 304 is inputted to the coilunit 304-1 only when a smoothing capacitor (not shown) of the rectifyingsection 303 is charged. Herein, the coil unit 304-1 has characteristicsinterfering the inflow of the rush current (e.g., 202 in FIG. 2).

[0033] To cut off the higher harmonics flowing into a standby powersupplier, a higher harmonics cut-off circuit could be installed on apower supply channel connected between a standby power smoothing circuitand the standby power supplier. However, when the higher harmonicscut-off circuit is also installed at the standby power supplier, becauseadditional construction of the power supply device of the video displayapparatus is needed, it has a bad influence upon weight in the videodisplay apparatus. In addition, because fabrication process isincreased, operation efficiency and productivity of the video displayapparatus may be lowered.

[0034] Operations of the power supply device of the video displayapparatus in accordance with the preferred embodiment of FIG. 3 will nowbe described. First, the filtering unit 302 cuts off EMI preferably byremoving noise element, etc. included in the AC power applied from theAC input block 301 and outputs the noise-removed AC power to therectifying section 303. In more detail, the filtering unit 302 removesthe noise element included in the AC power applied from the AC inputblock 301 and cuts off EMI by filtering the AC power applied from the ACinput block 301 and outputting the filtered AC power to the rectifyingsection 303.

[0035] The rectifying section 303 converts the filtered AC power into DCpower and supplies the converted DC power to the harmonic suppressor304. A certain ripple element is included in the DC power converted bythe rectifying section 303.

[0036] The harmonic suppressor 304 preferably cuts off or reduces thehigher harmonics generated because of the rush current by cutting offthe rush current included in the DC power converted by the rectifyingsection 303 and supplies the higher harmonics-cut off DC power to thesmoothing circuit 306. Herein, the control unit 305 can controloperations of the harmonic suppressor 304 according to a mode (e.g., astandby power supply mode or a main power supply mode) of the videodisplay apparatus.

[0037] The standby power supply mode is supplying low power to the videodisplay apparatus by receiving a request signal of a user through aremote controller (not shown) or power on/off switching (not shown)operation of the video display apparatus or the like in order to operatethe video display apparatus. The main power supply mode is supplyinghigh power to the video display apparatus by receiving a request signalof a user through a remote controller (not shown) or power on/offswitching (not shown) operation of the video display apparatus in orderto operate the video display apparatus.

[0038] Operations of the control unit 305 and the harmonic suppressor304 in the standby power supply mode will now be described. First, whena mode of the video display apparatus is switched into the standby powersupply mode by a request of the user or the like, the control unit 305outputs a control signal for stopping the operation of the operationunit 304-3 to the operation unit 304-3. The operation unit 304-3 turnsoff the switching unit 304-2 according to the control signal of thecontrol unit 305 in the standby power supply mode. When the operation ofthe switching unit 304-2 is turned off, the DC power rectified in therectifying section 303 is supplied to the smoothing circuit 306 throughthe coil unit 304-1 of the harmonic suppressor 304. In more detail, inthe standby power supply mode, because the rush current included in theDC power (e.g., low power) supplied to the smoothing circuit 306 islower than the rush current included in the DC power (e.g., high power)supplied to the smoothing circuit 306 in the main power supply mode, itis supplied to the smoothing circuit 306 only through the coil unit304-1 of the harmonic suppressor 304. Thus, the higher harmonicsincluded in the DC power (e.g., low power) can be cut off through thecoil unit 304-1.

[0039] Operations of the control unit 305 and the harmonic suppressor304 in the main power supply mode will now be described. When the videodisplay apparatus is in the main power supply mode, the control unit 305outputs a control signal for operating the operation unit 304-3 to theoperation unit 304-3. In the main power supply mode, the operation unit304-3 outputs a driving signal for switching the switching unit 304-2 tothe switching unit 304-2 according to the control signal of the controlunit 305. The switching unit 304-2 performs the on/off operation on thebasis of the driving signal. Accordingly, as shown in FIG. 4, the rushcurrent included in the DC power converted by the rectifying section 303is cut off by grounding the coil unit 304-1 when the switching unit304-2 is turned on. On the other hand, a normal current not includingthe rush current is outputted to the smoothing circuit 306 through thecoil unit 304-1 when the switching unit 304-2 is turned off, andaccordingly only the higher harmonics-removed DC power is supplied tothe smoothing circuit 306.

[0040] For example, in the main power supply mode, the switchingoperation unit 304-3 switches the current signal with a timing as thecurrent waveform 402 shown in FIG. 4 according to the control signal ofthe control unit 305. By switching the control signal within theenvelope level (e.g., sine wave or the like) of the voltage signal 401,the higher harmonics can be cut off by restraining the rush currentgeneration, and accordingly the higher harmonics-cut off DC power issupplied to the smoothing circuit 306. In more detail, in the main powersupply mode, because the DC power supplied to the smoothing circuit 306is high power, the rush current included in the DC power rectified inthe rectifying section 303 is cut off by grounding the coil unit 304-1of the harmonic suppressor 304, and the current not including the rushcurrent is supplied to the smoothing circuit 306 through the coil unit304-1 of the harmonic suppressor 304. Herein, the higher harmonicsincluded in the DC power (e.g., high power) is cut off by grounding thecoil unit 304-1. In addition, the higher harmonics cut-off DC powerincludes a certain ripple element.

[0041] Afterward, the smoothing circuit 306 smoothes the higherharmonics-removed DC power and respectively supplies the smoothed DCcurrent to the standby power supply unit 307 and the main power supplyunit 308. The standby power supplier 307 supplies the higherharmonics-removed stable DC power to the video display apparatus (notshown) as standby power. The main power supplier 308 supplies the higherharmonics-removed stable DC power to the video display apparatus as mainpower. Accordingly, in preferred embodiment of a power supply device andmethod of the video display apparatus in accordance with the presentinvention, by cutting off higher harmonics generated because of the rushcurrent inflow, standby power and main power based on the higherharmonics-removed stable DC power can be supplied to the video displayapparatus.

[0042] As described above, preferred embodiments according to thepresent invention have various advantages. In a power supply device of avideo display apparatus in accordance with preferred embodiments of thepresent invention, it is possible to reduce or cut off higher harmonicsapplied to the standby power supplier and the main power supplier in thestandby power supply mode and the main power supply mode. By cutting offhigher harmonics included in the DC power, supplying the higherharmonics-removed DC power to the main power supplier or the standbypower supplier through the smoothing circuit and controlling theharmonic suppressor selectively according to the standby power supplymode or the main power supply mode, it is possible to cut off or reducethe higher harmonics transmitted or transitioned to the main power lineor the main power supplier in the standby power supply mode, prevent orreduce erratic operation of other apparatus or the video displayapparatus and improve operational reliability of the video displayapparatus.

[0043] The foregoing embodiments and advantages are merely exemplary andare not to be construed as limiting the present invention. The presentteaching can be readily applied to other types of apparatuses. Thedescription of the present invention is intended to be illustrative, andnot to limit the scope of the claims. Many alternatives, modifications,and variations will be apparent to those skilled in the art. In theclaims, means-plus-function clauses are intended to cover the structuresdescribed herein as performing the recited function and not onlystructural equivalents but also equivalent structures.

What is claimed is:
 1. A power supply device of a video displayapparatus, comprising: a rectifier configured to convert AC power intoDC power; a harmonic suppressor coupled to the rectifier and configuredto reduce higher harmonics included in the DC power; a smoothing circuitconfigured to smooth the higher harmonics reduced DC power; a standbypower supplier coupled to the smoothing circuit and configured to supplythe smoothed DC power to the video display apparatus as standby power; amain power supplier coupled to the smoothing circuit and configured tosupply the smoothed DC power to the video display apparatus as mainpower; and a controller configured to control an operation of theharmonic suppressor.
 2. The apparatus of claim 1, wherein the harmonicsuppressor comprises: a coil serially-connected between the rectifierand the smoothing circuit in order to remove all the higher harmonicsincluded in the DC power converted by the rectifier and apply the higherharmonics reduced DC power to the smoothing circuit; a switch configuredto vary an amount of the DC power received by the smoothing circuit byselectively coupling a reference voltage to the coil; and a switchcontroller to operate the switch; wherein the controller controls theswitch controller to supply the DC power converted by the rectifier tothe smoothing circuit by selectively operating the switch in accordancewith each of a standby power supply mode and a main power supply mode.3. The apparatus of claim 2, wherein the reference voltage is a groundvoltage.
 4. The apparatus of claim 3, wherein the switch operates tosupply the DC power converted by the rectifier to the smoothing circuitby grounding the coil or passing the DC power through the coil.
 5. Theapparatus of claim 1, wherein the controller controls the singleharmonic suppressor to operate in a standby power supply mode forsupplying the standby power or a main power supply mode for supplyingthe main power.
 6. The apparatus of claim 5, wherein the controllercontrols the switch controller to supply the higher harmonics reduced DCpower to the smoothing circuit through the coil in the standby powersupply mode.
 7. The apparatus of claim 6, wherein the controllercontrols the switch controller to supply the higher harmonics reduced DCpower to the smoothing circuit through the coil or by grounding the coilin the main power supply mode.
 8. A power supply device of a videodisplay apparatus, comprising: rectifying means for converting AC powerinto DC power; harmonic suppressor means for removing higher harmonicsincluded in the DC power; smoothing means for smoothing the higherharmonics removed DC power; standby power means for supplying thesmoothed DC power to the video display apparatus as standby power; mainpower means for supplying the smoothed DC power to the video displayapparatus as main power; and controller means for controlling theharmonic suppressor to operate both in a standby power supply mode forsupplying the standby power or a main power supply mode for supplyingthe main power.
 9. The apparatus of claim 8, wherein the harmonicsuppressor means comprises: coil means for removing the higher harmonicsincluded in the DC power converted by the rectifying means and applyingthe higher harmonics removed DC power to the smoothing means; switchingmeans for applying the DC power converted by the rectifying means to thesmoothing means through the coil means by being turned off in thestandby power supply mode for supplying the standby power to the videodisplay apparatus and for applying the DC power converted by therectifying means to the smoothing means by being selectively turned onand off to correspondingly connect and disconnect the coil means to areference voltage in a main power supply mode for supplying the mainpower to the video display apparatus; and operation means forcontrolling an operation of the switching means based on a controlsignal of the controller means.
 10. The apparatus of claim 9, whereinthe controller means controls the operation means to turn off theswitching means in the standby power supply mode and turn on and turnoff the switching means in the main power supply mode.
 11. The apparatusof claim 8, further comprising: filtering means for removingelectromagnetic interference by filtering the AC power.
 12. A powersupply device of a video display apparatus, comprising: a filtering unitconfigured to remove electromagnetic interference by filtering AC power;a rectifying section configured to convert the filtered AC power into DCpower; a coil unit configured to cut off higher harmonics included inthe DC power converted by the rectifying section and applies the higherharmonics cut-off DC power; a switching unit configured to apply the DCpower converted by the rectifying section to the smoothing circuitthrough the coil unit by being turned off in a standby power supply modefor supplying the standby power to the video display apparatus, whereinthe switching unit provides the DC power converted by the rectifyingsection to the smoothing circuit by coupling the coil unit to areference voltage or through the coil unit by being selectively enabledin a main power supply mode for supplying the main power to the videodisplay apparatus; an operation unit configured to control an operationof the switching unit; a smoothing circuit configured to smooth thehigher harmonics cut-off DC power applied from the coil unit; a standbypower supplier coupled to the smoothing circuit and configured to supplythe smoothed DC power to the video display device as the standby power;a main power supplier coupled to the smoothing circuit and configured tosupply the smoothed DC power to the video display device as the mainpower; and a control unit configured to control the operation unit toturn off the switching unit in the standby power supply mode andselectively enable the switching unit in the main power supply mode;wherein higher harmonics generated by a rush current included in the DCpower converted by the rectifying section is cut off by coupling thecoil unit to the reference voltage.
 13. The device of claim 12, whereinthe switching unit directly selectively connects a ground voltagedirectly to an output terminal of the coil unit.
 14. The device of claim13, wherein the higher harmonics generated by the rush current includedin the DC power converted by the rectifying section is cut off bygrounding the coil unit.
 15. A power supply method of a video displayapparatus, comprising: converting AC power into DC power; removinghigher harmonics included in the DC power in each of a first powersupply mode for supplying power to a video display apparatus and asecond power supply mode for supplying power to the video displayapparatus; smoothing the higher harmonics removed DC power; supplyingthe smoothed DC power to the video display apparatus as standby power;and supplying the smoothed DC power to the video display apparatus asmain power.
 16. The method of claim 15, wherein the removing comprisesoperating a harmonic suppressor in accordance with the first mode andthe second mode, and wherein the higher harmonics are cut-off.
 17. Themethod of claim 16, wherein the first mode is a standby power supplymode and the second mode is a main power supply mode.
 18. The method ofclaim 17, wherein the removing comprises: selectively coupling a coil toremove the higher harmonics; connecting the coil to a reference voltagein the standby power supply mode; and selectively bypassing the coilfrom the reference voltage and connecting the coil to the referencevoltage in the main power supply mode in accordance with a controlsignal.